Moving a huge mass of equipment such as this will require a range of different systems.
Hydrostatic bearings will make the whole structure ‘float’ on a thin film of pressurized oil – the telescope will be so sensitive it will move with the touch of a hand. The hydrostatic bearings will ease the telescope’s moving parts, forcing pressurized oil underneath them so they move smoothly, accurately and with little effort. The oil will pass through a circuit where it will be cooled and returned to the bearings.
There are two types of hydrostatic bearings: elevation bearings – which will be in the elevation ring - to support the tube, and azimuth bearings – between the azimuth ring and the base of the mounting - to carry the load of the mount.
Movement will be induced by the motors. Unlike other telescopes, which use friction or geared drives, the GTC will have direct drive motors. This type of motor needs little maintenance, eliminates potential inaccuracy due to intermediary components and reduces friction.
The encoders, the telescope’s positioning devices, will be located in the azimuth and elevation rings and will be sensitive to movements as slight as hundredths of a micron. The information provided by the encoders will be used to calculate the telescope’s position so that the motors can move it in the right direction.